Structure and Function Analyses of the Thioredoxin 2 and Thioredoxin Reductase Gene in Pacific White Shrimp (<i>Litopenaeus vannamei</i>)

The thioredoxin (Trx) system is one of the most significant systems in living organisms as it regulates cellular redox reactions and plays a pivotal protective role within the cell by promoting redox homeostasis. <i>Trx</i> and thioredoxin reductase (<i>TrxR</i>) are the core...

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Main Authors: Tong Xu, Pei-Hua Zheng, Ke-Er Luan, Xiu-Xia Zhang, Jun-Tao Li, Ze-Long Zhang, Wei-Yan Hou, Li-Min Zhang, Yao-Peng Lu, Jian-An Xian
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Animals
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Online Access:https://www.mdpi.com/2076-2615/15/5/629
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Summary:The thioredoxin (Trx) system is one of the most significant systems in living organisms as it regulates cellular redox reactions and plays a pivotal protective role within the cell by promoting redox homeostasis. <i>Trx</i> and thioredoxin reductase (<i>TrxR</i>) are the core oxidoreductases of the Trx system. In this study, the novel full-length cDNAs of <i>LvTrx2</i> and <i>LvTrxR</i> were cloned from <i>Litopenaeus vannamei</i>. The ORFs of <i>LvTrx2</i> and <i>LvTrxR</i> were 453 bp and 1785 bp, encoding polypeptides consisting of 150 and 596 amino acids. Sequence alignment analysis revealed that the amino acid sequence of <i>LvTrx2</i> shared a high degree of identity (93%) with that of <i>Penaeus chinensis</i>, while in <i>LvTrxR</i>, it exhibited a similarity level of 95% with previously submitted <i>Penaeus chinensis</i> and <i>Penaeus monodon</i> sequences. Regarding tissue-specific expression patterns, <i>LvTrx2</i> showed its highest expression levels in hepatopancreas and gill. For <i>LvTrxR</i>, the highest expression was observed in gill followed by hepatopancreas and intestine. During exposure to ammonia-N, there was a significant upregulation in the relative mRNA levels of <i>LvTrx2</i> and <i>LvTrxR</i> in hepatopancreas and gill, with the peak values occurring at 24 h or 48 h of exposure. After LPS injection, the <i>LvTrx2</i> and <i>LvTrxR</i> transcripts in hepatopancreas and gill had different upregulated levels. These findings suggest that <i>LvTrx2</i> and <i>LvTrxR</i> play pivotal roles in enhancing stress resistance and bolstering antibacterial defense mechanisms in <i>L. vannamei</i>. To explore the roles, <i>LvTrx2</i> expression was knocked down in vivo to verify the defense mechanism against 4-NP stress. <i>LvTrx2</i> silencing in 4-NP-challenged shrimp could significantly induce the gene expression of antioxidant-related genes (except for <i>LvTrxR</i>) and aggravate the oxidative damage of lipids. This study suggests that the Trx system is involved in regulating the antioxidant processes, and <i>LvTrx2</i> and <i>LvTrxR</i> play a vital role in defense responses against environmental stress.
ISSN:2076-2615